Jet-treatment process for producing nonpatterned and line-entangled nonwoven fabrics



April 28, 1970 w. w. BUNTING. JR. ET AL 3,503,308

JET--TREATMEN R0 35 FOR ODUCING NONPATTERNED AND I -EN GLED .N OVENFABRICS Y L ()riginal Filed March 11, 1968 7 Sheets-Sheet 1 G 40 r- HT I4g ---wATER 24 INVENTORS IILLIAI IALLAR BU "l9. JR. F LII JAIES EV DELLIS "00K ATTORNEY I w.w. BUNTING,JR.. ETAL JET-TREATMENT PROCESS FORPRODUCI NG NONPATTERNED AND LINE-ENTANGLED NONWOVEN FABRICS OriginalFiled March 11, 1968 7 Sheets-Sheet 2 FIG.4

FIG.5

INVENTORS LU! !MUR BUITIIG, JR. FRANKLIN IE5 EVANS DAVID ELLIS "00KATTORNEY pr 1970 w. w. BUNTING, JR, ETAL 3,50

JET-TREATMENT PROCESS FOR PRODUCING NONPATTERNED AND LINE-ENTANGLEDNONWOVEN FABRICS lriginal Filed March 11. 1968 7 Sheets-Sheet 5 FIG-IOINVENTORS WILLIAM WALLAR aumme, JR.

Y n B N R S O N u w E In A m m f. S "L w N m M FD April 28, 1970 w, w,-nus; JR ET AL I 3,508,308

JET-TREATMENT PROCESS FORPRODUCI NG NONPATTERNED AND LINE-ENTANGLEDNONWOVEN FABRICS Original Filed March 11, 1968 7 Sheets-Sheet 4 g J a: I2 I; ,1 :3 IE I m w '5; F, a I 0- 31 III i m I 8 mvmoxs IILLIAII WALLERBUIITIIIG, JR. 3 FRANKLIN JAIIESEVAIIS o DAVID ELLIS HOOK BY ATTORNEYAprll 28, 1970 w w BUNTlNG, JR ET AL 3,508,308

JET-TREATMENT PROCESS FOR PRODUCING NONPATTERNED AND LINE-ENTANGLEDNONWOVEN FABRICS Original Filed March 11, '7 Sheets-Sheet 5 4- mvmons'ILLIAI IALLAR BUNTINGJR. FRANKLIN JAIIES EVANS DAVID ELLIS HOOK ATTOIQEY April 28, 1970 w, w, BUNTING, JR" ETAL 3,508,308

JET-TREATMENT PROCESS FOR PRODUCING. NONPATTERNED AND LINE-ENTANGLEDNONWOVEN FABRICS nal Filed March 11, 1968 7 Sheets-Sheet 6 FIG.

FIG. 13

i s i FIG. 15

\INVENTORS FRANKLIN JANES EVANS ATTORNEY April 28,\-l970 w. w. BUNTING,JR., ETAL 08 JET-TREATMENT PROCESS FOR PRODUCING NONPATTERNED ANDLINE-ENTANGLED NONWOVEN FABRICS Original Filed March 11. 1968 7Sheets-Sheet '7 FIG. I8

O.I INCH 0.1 INCH O.I INCH 0.1 INCH O. INVENTORS WILLIAM WALLER BUNTING,JRv

FRANKLIN JAMES EVANS BY DAVID ELLIS HOOK MZMW A TTOR NEY United StatesPatent M Int. Cl. D04h 1/46 US. Cl. 2872.2 9 Claims ABSTRACT OF THEDISCLOSURE Processes are disclosed for treating fibrous sheet materialswith streams of water or other suitable liquid. The liquid is forcedunder high pressure through nozzles, or orifices arranged along amanifold, to form fine streams. Fibrous sheet material on a supportingmember is traversed with the streams to entangle the fibers in a mannerwhich imparts strength and stability without the need for binder. Theexamples illustrate application of the process to a variety of fibroussheet materials, including treatment of batts of loose staple fibers orcontinuous filaments, to form coherent, highly stable, strong nonwovenfabrics which are randomly entangled and substantially nonpatterned orwhich have a repeating pattern of closely spaced lines of fiberentanglement.

CROSS-REFERENCES TO RELATED APPLICATIONS This is a division ofapplication Ser. No. 712,070, filed Mar. 11, 1968, as acontinuation-in-part of application Ser. No. 584, 627, filed Sept. 22,1966 (now abandoned) as a division of application Ser. No. 208,136,filed July 6, 1962 (now abandoned).

BACKGROUND OF THE INVENTION This invention relates to novel textileproducts and to a process for their production. More particularly, thepresent application relates to production of nonwoven fabrics bysubjecting bulk fibrous materials to the action of liquid streams.

The prior art discloses various processes in which fluids under pressurehave been used to treat textile materials. For example, dispersedstreams of water, provided by a solid cone spray nozzle supplied withwater at 70 to 100 pounds per square inch gauge pressure (p.s.i.g.),have been applied through spaced apertures against a fibrous startingmaterial so as to rearrange laterally the individual fibers into apattern determined by the pattern of the apertures. These prior artproducts rely on binder to attain strength.

Guerin US. Patent No. 3,214,819, issued Nov. 2, 196-5, teaches theformation of noncored felts, cored felts and felts with a backing, byapplying jets of liquid to a plurality of layers of loosely associatedtextile fibers to produce a reorientation of some fibers betweenlaminations to provide a fiber-locking and entanglement, in the product,having a strength equal to a normal needle 3,508,308 Patented Apr. 28,1970 loomed fabric and with greater flexibility and diversification. Thepatent also discloses that when an adhesive such as resin in liquid formis added the binder is permeated through the material to anchor thefibers in their new oriented form and increase the tensile strength andabrasion resistance. The present invention provides importantimprovements over the teaching of the Guerin patent.

SUMMARY OF THE INVENTION The present invention provides improvements inthe process for producing substantially nonpatterned nonwoven fabricfrom bulk fibrous materials wherein a layer of fibers on a supportingmember is treated with liquid jet streams to consolidate the fibers intoa self-coherent fabric. The invention provides a more efficient processwhich is suitable for producing more uniform and stronger nonwovenproducts. The invention is particularly useful for processingnonfeltable fibers and filaments, i.e., synthetic and cellulosic fibersand filaments, including cotton, rayon and cellulose derivatives.Preferred embodiments provide new smooth-surfaced textile fabrics havingsubstantially uniformly dense structures. Other advantages will becomeapparent from the specification and claims.

The process of the present invention comprises supporting a layer offibrous material on a smooth supporting member for treatment, jettingliquid supplied at a pressure of at least 200 pounds per square inchgauge from orifices less than about 0.015 inch in diameter to form finestreams having over 23,000 energy flux in footpoundals/inch second atthe treatment distance, and traversing the supported layer of fibrousmaterial with the streams along paths centered less than about 0.1 inchapart to apply a treatment energy of at least 0.1 horsepower-hour perpound of fabric product.

The above process is applicable to continuous filaments as well asfibers of textile length and shorter. Unless otherwise indicated thesewill be referred to as fibers. The fine liquid streams areadvantageously formed by jetting water from orifices 0.002 to 0.015 inchin diameter arranged in a line in a manifold at a frequency ofat least10 orifices per inch, and preferably 20 to 40 orifices per inch,although a frequency of 5 orifices per inch can also be used asillustrated in the examples. Orifices must be used which will provide atleast 23,000 foot-poundals/ inch second of energy flux at the treatmentdistance, as explained in detail subsequently. Preferably the streamsare essentially columnar.

The rate at which the layer of fibrous material is traversed with thestreams and the number of times the layer is treated should provide atotal treatment energy of at least 0.1 horsepower-hour per pound fabric(HP- hr./lb.). As subsequently explained, it is frequently desirable toaply much higher treatment energies. Adequate treatment with the streamswill provide strong, durable fabrics. =For products having sufiicientsurface stability to withstand repeated washing without the use ofbinders, the treatment energy is preferably greater than 1 HP- hr./lb.Preferably, water pressures of at least 500 p.s.i.g. are used to reducethe treatment time.

During treatment, the layer of fibrous material is supported by a memberwhich does not influence the arrangement of the fibers into a patterndependent on the supporting surface. This type of member will be simplycalled a smooth supporting member hereinafter, and it may be a solidplate, bar, roll or the like, or it may be a relatively smooth screen ofsufiiciently fine mesh so that the fibers are not rearranged into anypattern dependent on the screen pattern.

The process of the present invention may be used to produce two types ofnonwoven fabrics, namely (1) a line-entangled product and (2) asubstantially uniformly entangled product, depending upon whether thestreams of jetted liquid are allowed to act directly on the fibrouslayer or are oscillated or interrupted in their passage toward thelayer, the layer being treated on a supporting member as discussedabove. For either type of fabric, it has been found that a synergisticeffect with respect to producing a strong fabric (preferably having atensile strength of at least 2 lbs/in. per oz./yd. is obtained by theuse of small diameter orifices (0.002 to 0.010 inch in diameter), whichare closely spaced (at least per inch and preferably to 40 per inch) andhigh pressures (greater than 200 p.s.i.g. and preferably at least 500p.s.i.g.), for products weighing less than 10 ounces per square yard.

When the process of the present invention is operated so thatessentially columnar streams of liquid, such as water, emerge from theorifices and pass directly into contact with the layer of fibers (on thesupporting member), along parallel, continuous paths, which arestraight, curved or zig-zag, one produces a nonwoven fabric having linesof entanglement in a straight, curved or zig-zag pattern determined bythe paths of the streams and corresponding in number and frequency tothe number and frequency of the orifices. This type of line-entangledproduct may have a distinct jet-track pattern. The jet-track pattern can'be emphasized by carrying out the treatment so that the parallelstreams pass repeatedly along the same paths, as illustrated in Example2. Entanglement and hence strength can be increased by repeatedtreatment or by prolonged treatment, for example by slow passage of thestreams over the layer.

When the above treatment is carried out while oscillating the jetstreams at high frequency (e.g., 300 cycles per minute for 2yards/minute web speed), or while interrupting them, soft,smooth-surfaced and substantially uniformly dense products can be madeeven from lightweight materials, e.g., as shown in Example 9.Interrupting the jet streams before they reach the fibrous layer iscarried out so as to form intermittent essentially columnar streams. Apreferred method of accomplishing this is to place a screen or the like(referred to hereinafter as a streams-interrupting-member) in the pathof the jet streams at a point between the orifices and the plane of thefibrous layer and to oscillate the streams-interrupting-member throughthe streams to provide a high frequency of interruption duringtreatment. The streamsinterrupting-member is not used to restrain thefibrous layer or to influence rearrangement of the fibers of the layerinto a pattern. Preparation of nonwoven textile fabrics by this methodis illustrated in Example 10.

The substantially nonpatterned, nonwoven textile fabrics of the presentinvention are generally smooth surfaced, dense and strong; theirstrength is due to fiber entanglement, which is achieved without the useof feltable fibers (such as Wool) or of conventional needle-punch- Aparticular advantage of the present invention is that these dense,substantially nonpatterned, nonwoven fabrics can be made at low basisWeights of less than 8 ounces per square yard, and much lower, as shownin the examples.

The substantially uniformly dense structure of the products is readilyapparent when viewed by transmitted light as illustrated in FIGURE 17.The nature of the interentangled fiber structure is illustrated inFIGURES 18 to 20, and can be seen with a, microscope. The substantialabsence of clusters of fiber segments oriented transversely to the planeof the fabric distinguishes these products from heavy needle-punchedfelts or similar products of processes in which fiber webs are treatedat spaced sites. FIGURE 21 illustrates the clusters of transverse fibersegments in a commercial needle-punched felt. When such photomicrographsare evaluated for clusters as disclosed near the end of thespecification, clustering coefficients of less than 2.5 are found forstructures of types shown in FIGURES 18 to 20, as contrasted with aclustering coefiicient of 3.8 for FIGURE 21.

Determination of entanglement completeness, entanglement frequency andfiber-interlock values is described near the end of the specification.By bond-free is meant that the fibers of the nonwoven fabric are notadhered with binder or interfiber fusion bonds. In other words, thenonwoven fabric is tested to determine the properties due solely to theinterentangled fiber structure.

By interentangled is meant that the individual fibers of the structureare intertwined, tangled, interlaced and otherwise joined with eachother so as to be virtually inseparable. The process may be applied topreselected areas of the layer of fibrous material up to and includingits entire area. When the treated area is viewed in cross-section, it isobserved that a number of fiber segments have been reoriented in thedirection generally perpendicular to the plane of the nonwoven fabric bythe action of the streams. It is believed that these fibers contributeto the strength of the nonwoven fabric by serving to tie other fibers inplace.

The term layer of fibrous material includes any layer composed offibrous elements in the form of staple fibers, continuous filaments,and/or yarns in the form of mats, batts, webs or the like and includinglayered composites and blends thereof.

Nonwoven fabrics having particularly high levels of drape andconformability can be obtained by using crimpable, spontaneouslyelongatable, or elastic fibers as one of .the components of the fibroussheet material and developing the latent properties of the fiber afterformation of the nonwoven fabric.

BRIEF DESCRIPTION OF THE DRAWINGS This invention can be more thoroughlyunderstood by the following discussion, with reference to the drawingswherein:

FIGURE 1 shows a schematic view of one type of apparatus for carryingout the process of this invention.

FIGURES 2a-2c are axial cross-sectional views of suitable nozzles.

FIGURE 3 is a cross-sectional view, taken along the longitudinal axis,of a nozzle which may be used to produce intermittent columnar flow.

FIGURE 4 is a schematic view of one apparatus for carrying out theprocess of this invention.

FIGURE 5 is a schematic isometric view of an apparatus for the highspeed production of a continuous nonwoven fabric.

FIGURE 6 is a schematic isometric view of an apparatus for the highspeed, continuous production of nonwoven fabrics.

FIGURE 7 is a schematic side view of apparatus for continuously feedingand opening staple fibers, forming a Web and jet treating the web toform nonwoven fabrics.

FIGURE 8 is an enlarged side-sectional view of one of the jet-treatingmachines in FIGURE 7.

The upstream face is the one nearest the jet streams during finaltreatment.

FIGURE 14 is a photograph showing the downstream face of the fabric ofFIGURE 13. The downstream face is that adjacent the supporting screenduring final treatment,

FIGURE 15 and FIGURE 16 are X enlarged views of the fabrics of FIGURES13 and 14.

FIGURE 17 is a photomicrograph taken by light transmitted through fabricA of Example 10 to show the absense of pattern. The magnification isindicated by the scale beside the figure.

FIGURES 18 to 20 are photomicrographs, made with a scanning electronmicroscope, showing sectional views of the interiors of fabric producedas described in Examples 10A, 10B and 11, respectively. The section istaken in the plane of the fabric, approximately midway between the twofaces. The scales beside the figures indicate magnification.

FIGURE 21 is a photomicrograph of a microsection slice takenapproximately midway between the two faces of a commercialneedle-punched felt to illustrate the transverse fiber clusterscharacteristic of such treatments. Magnification is shown by the scalebeside the figure.

EQUIPMENT A relatively simple form of equipment for treating fibrouswebs with water at the required high pressure is illustrated inFIGURE 1. Nitrogen under a pressure of 2,000 lbs./ sq. in. in a bottle 1is connected through a regulating valve 2 and pipe 3 to one chamber 4 ofa hydraulic accumulator 5. The hydraulic accumulator is separated intotwo chambers 4 and 6 by a flexible diaphragm 7. The second chamber 6 isconnected to a nozzle 20 through a pipe 8 in which a valve 9 isprovided. Water is supplied to the second chamber from a source of water(not shown) through a valve 10 and a pipe 11. When water is added,pressure is released from the first chamber through pipe 12 by opening avalve 13. Starting with an unpressurized situation, the system ischarged by closing regulating valve 2, opening valve 13 so thatatmospheric pressure prevails in the system, closing valve 9 and openingvalve 10 to admit water at pressure of about 40 lbs/sq. in. gauge; thewater pushes the diaphragm 7 of the accumulator 5 to the right intochamber 4, thus filling chamber 6. After chamber 6 is filled, valves 10and 13 are closed, regulating valve 2 is opened and adjusted to delivernitrogen at about 2,000 lbs/sq. in. gauge to the chamber 4; thispressurizes the water in chamber 6 so that the system is ready todeliver water to the nozzle 20 through line 8 whenever valve 9 isopened. The nozzle 20 may be any one of a variety of nozzles dependingon the effect desired. Various types of nozzles which may be used areshown in FIGURES 2a-2c.

The fibrous sheet material to be treated 14 is placed on a generallyrectangular wire screen carrier 15 situated below the verticallydisposed nozzle and supported on a horizontal, fiat plate 16. A jack 17of the scissors type supports plate 16 so as to be verticallyadjustable, providing for adjustment in the distance between the tip ofthe nozzle 20 and the screen 15. The screen, in this case is an ordinarywoven one of 80 by 80 mesh per inch and is made of 0.005 inch diameterstainless steel wire. The screen is not secured to plate 16 but is freeto be moved manually in a horizontal plane in any direction. The plate16 is provided with a vent hole 18 which is vertically aligned with theaxis of the nozzle 20 so as to pass liquid which issues from the nozzle;a tray 19 is adapted to catch any liquid which falls through vent hole18.

The following example will illustrate operation of this apparatus fortreating a staple fiber batt to produce a jettrack-patterned product. Aloose batt 14 of randomly arrayed staple fibers is laid on screensupport 15. The jack 17 is adjusted vertically so as to position theupper face of the batt about 1 inch below the tip of nozzle 20. The

batt is then exposed to the action of the high velocity stream of waterwhile simultaneously being passed horizontally along a straight line inone direction. A series of batts, ranging in thickness from to 3 inchesare pr0cessed in this manner, successive passes being made along linesparallel to the first pass. Some of the batts are also subjected tosuccessive passes along lines at right angles to the first passes. Inall instances, it is observed that along the lines of liquid treatment,the fibers of the batt are driven generally downward, thus tending toconsolidate the batt; in addition, the fibers are entangled andintertwined with one another, in general, in a discrete continuous linecorresponding to the path of treatment of the liquid stream.

The nozzle shown in FIGURE 2a is adapted to be connected to pipe line 8and consists of a body 21 having an axial bore 22 which is generallyclosed at the bottom and except for a pair of orifices 23, 24 which arecoplanar with each other and with the axis of the bore 22 and areinclined toward each other, in the direction of the liquid flow, at anincluded angle A. This angle is about 20 to 25 and the orifices are0.007 inch in diameter. Liquid streams emerging from the orifices 23, 24are continuous but tend to break up as the two streams impinge on eachother. In the use of this type of nozzle, the sheet material is placedeither above or at the point of intersection of the streams.

A variation of the nozzle of FIGURE 2:: is shown in FIGURE 2b, in whicha pair of 0.007" diameter orifices 23, 24 are disposed parallel to eachother and coplanar with the bore 22.

The nozzle shown in FIGURE 20 is similar to that shown in FIGURE 2a,except that a single central orifice 24 is used; this orifice is coaxialwith the bore 22. At a pressure of about 1,000 lb./sq. in., a single0.007 inch diameter orifice will deliver about 14.5 lbs. of water perhour, and at 2,000 lbs./ sq. in., 20.5 lb./hr.

The nozzle shown in FIGURE 3 can be used when intermittent flow isdesired. It resembles a diesel-engine type of fuel injection nozzle. Thebody 21 has an axial bore 22 in which a close-fitting cylindricalplunger 30 is situated. The plunger has a conical tip 31 adapted to forma fluid-tight seal in a mating conical seat 32 at the lower part of thebore 30. Axial passage 33, of smaller diameter than bore 22, opensdownward from the conical seat. An annular space 34 is cut into theconical seat. A liquid supply passage 35 is drilled downward throughbody 21 along side of bore 22 to communicate with the annular space.Plunger 30 is urged downward against the conical seat at a pressuredetermined by adjusting a spring 36. When this pressure is exceeded byliquid supplied to space 34 through passage 35, then plunger 30 isforced upward and liquid passes downward through axial passage 33. Anozzle tip 37 screws onto the lower end of body 21 and is provided withorifices, such as orifices 24, 25, 26 which direct liquid from passage33 downward in columnar flow. Any of the orifice arrangements shown inFIGURES 2a-2c can be used. Another suitable tip is provided with acentral orifice 0.50 mm. in diameter surrounded by six orifices 0.45 mm.in diameter and equally spaced on a 50 included angle cone in the mannerillustrated for orifices 24, 25 and 26.

When the nozzle of FIGURE 3 is used in the apparatus of FIGURE 1,intermittent impulses of high pressure liquidare supplied by anintensifier 40, a standard piece of equipment which, when supplied withdriving air at a pressure of 40 p.s.i.g., will boost the water pressureto about 20,000 pounds per-square-inch gauge in short pulses having afrequency of about one pulse per second. This is supplied to nozzle 20through line 41 provided with a throttling valve 42. Water and air aresupplied to the intensifier through lines 43 and 44, respectively. Thehydraulic accumulator system described previously is not used when theintensifier is used, so line 8 is disconnected. The fibrous sheetmaterial is treated in the same manner as before but the pulses of highvelocity liquid, formed with the intensifier and nozzle of FIGURE 3,pierce the sheet material at intervals along the path of traverse underthe nozzle. Short discrete seam-like lines of entanglement and/or pointseams are produced at each spot pierced by the intermittent stream. Thefrequency and duration of the liquid pulses may be controlled byadjusting spring 36, by throttling with valve 42, and by selection ofthe nozzle tip 37, to produce streams in the range of 0.0005 to 0.005inch in diameter which impinge on the fabric at pressures of the orderof 3,000 pounds per square inch in the desired seaming pattern.

Instead of using individual nozzles and subjecting the fibrous sheet toa number of successive passes, a plurality of nozzles arranged in a rowand spaced any desired distance apart may be used to increase the areaof treatment in a single pass. By this method, parallel seams, i.e.,lines of entanglement, as close to each other as 0.025 inch (40 perinch) or less can be produced in batt materials in two directions,changing their appearance to that of a woven fabric. Apparatus for thecontinuous production of a nonwoven fabric by this process is shownschematically in FIGURE 5.

In the apparatus, a horizontal, belt-type screen conveyor 50 is adaptedto transport a batt of fibers 28 in the direction of the arrow.Transverse of the conveyor is a plurality of spaced stationary nozzles51 which are adapted to modify the batt along lines disposed in thedirection of batt travel as denoted by the lines 52. Downstream of thenozzles 51 are one or more nozzles 53 which are arranged to bereciprocated transversely of the batt (by a mechanism not shown) so asto modify the batt along the lines 54 which are generally perpendicularto the lines 52. Still further downstream is a series of rollers 55a, b,c and d which change the direction of the modified batt, causing it tobe momentarily immersed in a liquid filled tank 56 for shrinkage,dyeing, bleaching, etc., as desired. At the extreme right is a windup 58for receiving product 57. The roller 55d may be used for pressing orwringing the modified batt, heat treating or drying it, embossing it,etc.

In operation, a batt of fibers 28 is advanced from left to right underthe various nozzles where it is modified (either continuously orintermittently) in one or more directions; if desired, the batt thentravels to the liquid bath where it is shrunk, being subsequently driedor partially dried, and finally wound on a suitable core.

An apparatus for the continuous treatment of fibrous sheets is shown inFIGURE 4. Water at normal city pressure of approximately 70 pounds/ sq.in. gauge is supplied through valve 81 and pipe 82 to a high pressurehydraulic pump 83. The pump may be a double-acting, single plunger pumpoperated by air from line 84 (source not shown) through pressureregulating valve 85. Air is exhausted from the pump through line 86.Water at the desired pressure, e.g., 2000 lbs./sq. in., is dichargedfrom the pump through line 87. A hydraulic accumulator 88 is connectedto the high pressure water line 87. The accumulator serves to even outpulsations and fluctuations in pressure from the pump 83. Theaccumulator is separated into two chambers 89 and 90 by a flexiblediaphragm 91. Chamber 90 is filled with nitrogen at a pressure of /3 to/3 of the desired operating Water pressure and chamber 89 is then filledwith water from pump 83. Nitrogen is supplied through pipe 92 and valve93 from a nitrogen bottle 94 equipped with regulating valve 95. Nitrogenpressure can be released from the system through valve 96. Water at thedesired pressure is delivered through valve 97 and pipe 98 to manifold99 supplying orifices 100. The fine, essentially columnar streams ofwater 101 emerging from orifices 100 impinge on the material beingtreated 102, which is supported by conveyor 103.

The streams are traversed over the web, by moving the conveyor screen103 and/or the manifold 99, until the web is treated in the desiredareas at high energy flux. In general, it is preferred that the initialfibrous layer be treated by moving conveyor screen 103 under a number offine, essentially columnar streams, spaced apart across the width of thematerial being treated. Rows or banks of such spaced-apart streams canbe utilized for more rapid, continuous production of nonwoven fabrics.Such banks may be at right-angles to the direction of travel of the web,or at other angles, and may be arranged to oscillate to provide moreuniform treatment. Streams of progressively increasing energy flux maybe impinged on the web during travel under the banks. The streams may bemade to rotate or oscillate during production of the nonwoven fabrics,may be of steady or pulsating flow, and may be directed perpendicular tothe plane of the web or at other angles provided that they impinge onthe web at suificiently high energy flux.

Another apparatus suitable for the continuous production of nonwovenfabrics in accordance with the present invention is shown schematicallyin FIGURE 6. A pump 65, which may be one of the types used for supplyingwater to high pressure steam boilers, is used to provide liquid at therequired pressure. A fibrous layer 60, prepared by conventional meanssuch as a card machine or random web air-laydown equipment, is suppliedcontinuously to a moving carrier belt 61 of flexible foraminousmaterial, such as a screen or a solid belt. The carrier belt issupported on two or more rolls 62 and 63 provided with suitable drivingmeans (not shown) for moving the belt forward continuously. Six banks oforifice manifolds are supported above the belt to impinge liquid streams64 on the fibrous layer at successive positions during its travel on thecarrier belt. The fibrous layer passes first under orifice manifolds 66and 68, which are adjustably mounted. Orifice manifolds 74, 75, 76 and77 are adjustably mounted on frame 78. One end of the frame is supportedfor movement on a bearing 79, which is fixed in position. The oppositeend of the frame is supported on oscillator means for moving the frameback and forth across the fibrous layer.

High pressure liquid is supplied from the reservoir to the orificemanifolds through pipe 18. Each manifold is connected to pipe 18 througha separate line which includes flexible tubing 48, a needle valve 45 foradjusting the pressure, a pressure gage 46, and a filter 47 to protectthe valve and jet orifices from foreign particles. As indicated on thegages in the drawing, the valves are adjusted to supply each successiveorifice manifold at a higher pressure, so that the fibrous layer 60 istreated at increasingly higher energy flux during travel under theliquid streams 64. However, the conditions are readily adjusted toprovide the desired treatment of different initial fibrous layers.

FIGURE 7 illustrates a combined apparatus for continuous processing ofstaple fiber stock, as received from the supplier, to convert thematerial into a nonwoven fabric. The stock is fed through a conventionalopener or picker 788 and the opened stock is carried on conveyor belt789 to a conventional card machine. The stock is fed by lickerin 780 tocard cylinder 781 where the fibers are combed, the fibers are collectedon dotfer 785 and are taken off through calender 786 and are introducedinto a layer-forming apparatus. The fibers are carried on elevatingapron 755 until removed by stripper apron 758 and are collected oncondenser roll 763 to form a preliminary layer. The lickerin 767separates the fibers and the fibers are deposited on condenser roll 771to form a uniform layer of randomly arranged fibers. The layer issupported on conveyor belt 774 until it passes through calender 775 tobe made sufficiently selfsupporting for subsequent treatment. Theresulting layer 778 passes to the jet-treating apparatus, describedbelow, for conversion to a nonwoven fabric. Apparatus for continuousdrying and windup of the fabric is also indicated.

The layer-forming apparatus processes a given weight of material at arelatively slow rate, whereas the jettreating apparatus is capable ofhigh speed operation. Increasing the speed of the layer-formingapparatus will result in a lighter weight layer. Therefore, it may bedesirable to provide more than one layer-forming apparatus, combine thelayers, and feed the combination of layers to the jet-treatingapparatus. When the layers are of the same material, the treatment willproduce a homogeneous product with no evidence of lamination. However,different types of layers can be combined for special purposes and theywill be securely entangled together by the jet treatment.

The jet-treating apparatus shown has three treatment drums 790, 791 and792. With this arrangement, the fabric formed on the first drum can betreated from the reverse face on the second drum and, if desired, givenan additional treatment on the third drum, all in a continuous,uninterrupted operation. However, one or two of the drums can beby-passed when treatment thereon is not desired. As shown in FIGURE 7,the layer 778 travels continuously from the layer-forming apparatus tothe first treatment drum 790. A guide roll 793 is shown, and additionalguiding or supporting means may be provided in order to feed the layersmoothly onto the cylindrical surface of the drum. The drum rotatescounter-clockwise and carries the layer beneath a plurality fjet-treatment manifolds 794. The fabric produced then leaves the firstdrum and travels over a series of guide rolls 795 to the secondtreatment drum 791. This drum rotates clockwise and the fabric is fedonto it so that the previously treated face is next to the cylindricalsurface of the drum. The fabric is carried beneath a plurality ofjet-treatment manifolds 796 to treat the face of the fabric opposite tothat previously treated. From the second drum the fabric is guided by aseries of rolls 797 to the third treatment drum 792. This drum rotatescounter-clockwise to carry the fabric beneath a plurality ofjet-treatment manifolds 798. This completes the treatment with liquidjets and the fabric leaves the drum at guide roll 799.

The jet-treated fabric passes to a wringer 700 to partially remove thetreating liquid. The fabric is guided by a series of rolls 701 toconventional drying cans or drums 702, which are heated to dry thefabric. The dry fabric proceeds to a conventional type of fabric windup703.

The used treating liquid falls into a drip tank 705 and is recovered,except for a small amount carried in the fabric to the drivingapparatus. The liquid is withdrawn from the tank through drain 706, ispassed through a filter 707 to remove any fibers or foreign matter, andcontinues through pipe 708 to pump 709. A multiple-piston,positive-displacement pump powered by an electric motor 710 ispreferable. A multiple-stage centrifugal pump can be used, but is lessefficient for pumping large volumes of liquid at high pressure. Since apiston pump causes pulsation surges, even when there are five or morepistons, a pulsation dampener 711 is provided in high pressure pump line712. A conventional fluid-filled, in-line pulsation dampener ispreferable in large scale operation, instead of the gas-dampener shownin FIGURE 4, because of the simplicity and greater safety provided whenhigh pressure liquid is supplied at a substantial rate. The treatingliquid flows from dampener 711 to a second filter 713 designed to removeany remaining particles of material large enough to plug the jetorifices. A pleated woven screen which will remove any particles oflarger than 25 microns in size is preferred. The filtered liquid thenflows into a feed manifold 714 which supplies the jet manifolds 794, 796and 7 98. Conventional pressure-control and highpressure-relief valves(not shown) should be provided to supply the liquid at the desiredpressure with safety.

Further details of the jet treating apparatus are shown in FIGURE 8. Thesingle treatment drum illustrated is similar to the third drum of FIGURE7 and the elements are correspondingly numbered. The fibrous materialfor treatment may come directly from the layer-forming apparatus,without previous jet treatment. Layer 778 is guided by rolls 797 ontothe cylindrical surface of the treatment drum 792, is carried under jetmanifolds 798, leaves the drum at guide roll 799, passes through Wringer700, and is guided by rolls 701 to drying apparatus.

The treatment drum is constructed so that the cylindrical surfacecontacting the fiber layer is a fine mesh screen or solid surface. Amember which does not have suificient rigidity, such as a woven wirescreen, must be supported. A honeycomb support 115, made of thin sheetmetal with about A; inch cells and at least 1 inch in thickness, ispreferred. The circular ends of the treatment drum rest on rollers 116.

The jet manifolds 798 are mounted on frame 117 which is supported onbearing blocks 118 at four corners of the frame. Drive means can beconnected to the frame by means of an eccentric to impart a circularoscillation to the frame and the jet manifolds mounted thereon. The jetmanifolds are mounted on the frame by adjustable means 119 and aresupplied with high pressure liquid through flexible hoses 120, which areconnected to high pressure manifold 714 by suitable fittings 121.

FIGURE 9 is is an isometric view of a portion of jet manifold 798, shownat a larger scale and with the parts separated for clarity. Along thecentral axis of flat metal strip 122 are equally-spaced jet orifices123. Above this jet strip is a perforated filter plate 124 which has thesame outer dimensions as the jet strip but is curved upward along thecentral axis so that the plate is spaced away from the jet orifices. Theplate is perforated with holes 125, which should not be larger than thejet orifices if intended to catch particles of foreign matter beforethey can plug the jet orifices. The holes are preferably smoothlyrounded and uniformly arranged along the curved portion of the plate toprovide an even flow of liquid to the different jet orifices. Asufficient number of holes to provide about 3.5 percent open areaproduces an even flow of liquid without excessive pressure drop throughthe filter plate. The manifold body 126 has an undercut portion 127, forreceiving the filter plate and jet strip, and has a slot 128 which formsa liquid chamber above the filter plate. Fitting 129 connects toflexible hose for introducing high pressure liquid into the chamber. Aheavy retainer plate 130 is secured to the manifold body by bolts 131 tohold the filter plate and jet strip in place in undercut portion 127with a liquid-tight seal. A slit 132 extends along the central axis ofthe retainer plate to expose the jet orifices 123.

PROCESS The mechanism of the process of this invention appears to be onein which the fibers of the sheet material are caused to move,intertwine, or interlace with other fibers under the influence of highvelocity liquid streams. The behavior of the fibers is best describedwith reference to FIGURES 10, 11 and 12. FIGURE 10 shows a crosssectionof a substantially unmodified batt of randomly arrayed fibers. It may beseen that carded and cross-lapped filaments are arrayed in strata inwhich individual filaments are more or less parallel to the horizontal;the filaments are not parallel to eachother but are dispersed more orless randomly. The approximate boundaries of the strata are defined byhorizontal lines; these lines are not intended to depict staple fibers.The behavior of one filament 170, marked with Xs along its length, isreviewed below.

In FIGURE 10, the filament is seen to lie in the unmodified batt nearthe top of the batt and generally parallel to the plane of the batt.Liquid streams 138 are shown impinging on the top face of the batt.

FIGURE 11 shows the same batt after a short duration exposure to a highvelocity liquid stream 138. In FIGURE 11, the filament 170 is seen to bedriven substantially through the entire thickness of the batt at twopoints 171 and 172. The liquid streams penetrate the full thickness ofthe batt and impinge upon the backing. The primary function of thebacking is to serve as a support for the batt material. Preferably ascreen or similar material, which will permit the flow of watertherethrough, is used. As it impinges on the backing, the stream or aportion thereof may be deflected, i.e., proceed in a generallyhorizontal direction Or in the plane of the batt, carrying filamentstherewith as shown by the loop in the filament at point 173. At thisstage, the filament 170 is rather thoroughly entangled with itsneighbors and vice versa. In effect, the various starata of the batt aresewn or stitched together by the migration and interentangling of thefibers.

FIGURE 12 shows the same batt after it has been manually turned over andtreated with high velocity liquid streams on its reverse side. It isseen that further inter-entanglement and intertwining of the filamentsoccurs in random fashion so that the batt becomes highly coherent in theregion in which it is treated by the liquid streams. Examination of thetreated batt reveals that some filaments essentially pierce the batt atseveral different locations, thus acting as randomly dispersed sewingthreads. The treated batt generally exhibits considerable tensilestrength on a three-dimensional scale and also shows a markedlyincreased resistance to surface abrasion.

While the description just given does not specify the area of the battthat was treated, obviously any area up to and including the total areamay be treated depending on the type of end product desired.

In order to produce high-strength nonwoven fabrics by the presentinvention, it is essential that the initial material be subjected to theaction of streams of a noncompressible fluid at sufficiently high energyflux and for a sufiicient amount of treatment to entangle the fibersthereof. The energy flux EF of the streams will depend upon the jetdevice used, the pressure of the liquid supplied to the jet orifice, andthe orifice-to-web spacing during treatment. The liquid initially formsa solid stream, i.e., an unbroken, homogeneous liquid stream. Theinitial energy flux, in foot-poundals per square inch per second, isreadily calculated by the formula,

EF =77 PG/ a where:

P=the liquid pressure in p.s.i.g.,

G=the volumetric flow of the stream in cu. ft./minute,

and

a=the initial cross-sectional area of the stream in square inches.

The value of G for use in the above formula can be obtained by measuringthe flow rate of the stream. The initial cross-sectional area a, whichis inside the jet device, can be determined by measuring the actualorifice area and multiplying by the discharge coefficient (usually0.64), or it can be calculated from measured flow rates. Since the areaa corresponds to solid stream flow, the above formula gives the maximumvalue of energy flux which can be obtained at the pressure and flow rateused. The energy flux will usually decrease rapidly as the streamtravels away from the orifice, even when using carefully shapedorifices. The stream diverges to an area A just prior to impact againstthe web and the kinetic energy of the stream is spread over this largerarea. The cross-sectional area A can be estimated from photographs ofthe stream with the web removed, or can be measured with micrometerprobes. The energy flux is then equal to the initial energy flux timesthe stream density ratio 12 (a/A). Therefore, the formula for energyflux at the web being treated is:

EF =77 PG/A ft.-poundals/in. sec.

The value of A increases with the orifice-to-web spacing and, at a giventreatment distance, the value depends upon the jet device and the liquidsupply pressure used. A pressure of 200 p.s.i.g. can provide sufficientenergy flux for several inches when using a highly eflicient jet device,e.g., as in Examples 1, 2, 3B, 4B, 6 and 7. With other jet devices, theenergy flux of a stream may become too low in a relatively shortdistance even when using higher pressures, due to the stream breaking upand losing its columnar form. When this occurs, there is a suddenincrease in the value of A and the energy flux drops rapidly. Since thestream may become less stable when higher pressures are used, the energyflux at a given treatment distance may actually decrease when the jetorifice pressure is increased to provide a higher initial energy fluxPG/a. Some stream density a/A and energy flux determinations for waterstreams from drilled-tube orifice manifolds, of types used in Examples3A, 4A and 5A are given in the following tables:

Distance Below Orifice For 3 mil orifice diameter inch inch 1.5 inch 200p.s.i.g.:

Stream density (a/A) 0. 0758 0. 0625 0. 0545 Energy flux 85, 000 70, 00061, 000 500 p.s.i.g.:

Stream density (a/A) 0.0758 0.0522 0.0405 Energy fluX 330, 000 230, 000180, 000 1,000 p.s.i.g.:

Stream density (a/A) 0.0758 0. 0441 0. 0349 Energy flux 940, 000 540,000 430, 000 1,500 p.s .i.g.:

Stream density (a/A). 0.0758 0.0405 0. 0304 Energy flux 1, 720, 000 920,000 600, 000

For 5 mil Orifice diameter 200 p.s.i.g.:

Stream density (u/A) 0.241 0. 103 0.0785 Energy flllX 270, 000 115, 00088, 000 500 p.s.i.g.:

Stream density (a/A) 0. 214 0. 0763 0. 0565 Energy flux 930, 000 330,000 250, 000 1,000 p.s.i.g.:

Stream density (a/A) 0. 0.0595 0. 0108 Energy fiux 2, 340, 000 730, 000130, 000

For 7 mil Orifice diameter 200 p.s.i.g.:

Stream density (a/A) 0. 357 0.125 0.0563 Energy flux 400, 000 140, 00063, 000 500 p.s.i.g.:

Stream density (a/A) 0.281 0. 097 0. 037 Energy flux l, 225, 000 421,000 162, 000 1,000 p.s.i.g.:

Stream density (a/A) 0. 236 0.079 0. 0196 Energy flux 2, 910, 000 972,000 242, 000 1,500 p.s.i.g.:

Stream density (a/A) 0. 236 0. 0645 0.0125 Energy flux 5, 350, 000 1,460, 000 283, 000

In the process of the present invention, the web is treated with streamsof water jetted at high pressure and having an energy flux EF of atleast 23,000 ft.-poundals per inch second. Such streams are preferablyobtained by propelling a suitable liquid, such as water, at highpressure through small-diameter orifices under conditions such that theemerging streams remain essentially columnar at least until they strikethe initial material. By essentially columnar is meant that the streamshave a total divergence angle of not greater than about 5 degrees.Particularly, strong and surface-stable fabrics are obtained withhigh-pressure liquid streams having an angle of divergence of less thanabout 3 degrees.

The amount of treatment must be sufiicient and is measured by energyexpended per pound of fabric produced. The energy E, expended during onepassage under a manifold in the preparation of a given nonwoven fabric,in horsepower-hours per pound of fabric, may be calculated from theformula:

where:

Y=number of orifices per linear inch of manifold,

P=pressure of liquid in the manifold in p.s.i.g.,

G=volumetric fiow in cu. ft./min./orifice,

s=speed of passage of the web under the streams, in

ft./min., and

b=the weight of the fabric produced, in oz./yd.

The total amount of energy expended in treating the web is the sum ofthe individual energy values for each pass under each manifold, if thereis more than one.

When treating fibrous material with streams of water impinged on thematerial at an energy flux EF of at least 23,000 ft.-poundals/in. sec.,jet-track-patterned entangled nonwoven fabrics can be prepared atexpenditures of energy of at least about 0.1 HP-hr./lb. of fabric. Atany given set of processing conditions, surface stability of thenonwoven fabric obtained (i.e., the resistance of the fabric to surfacepilling and fuzzing) can be improved by increasing the total amount ofenergy E used in preparing the fabric. There is, however, a maximumenergy of about 5-10 HP-hr./lb. beyond which little additional surfacestability is developed. For products with sufiicient surface stabilityto withstand repeated launderings, such as might be required for certainapparel and other uses, an energy flux EF of at least 100,000ft.-ponndals/in. sec. and an energy E greater than 1 HP-hr./ lb. offabric are preferred.

The process of the present invention may be used to produce entanglednonwoven fabrics from any type of loose fibrous web, batt, or sheet. Theease with which a given web can be entangled is dependent upon manyfactors, and process conditions may be chosen accordingly. Fibermobility also has a bearing on the ease with which a web can beprocessed. Factors which influence fiber mobility include, for example,the density, modulus stiffness, surface-friction properties, denier,crimp and/or length of the fibers in the web. In general, fibers whichare highly wettable, or have a high degree of crimp, or have a lowmodulus or low denier, can also be processed more readily.

If desired, the initial fibers or layer may be treated first with awetting agent or other surface agent to increase the ease of processing,or such agents may be included in the liquid stream.

Depending upon the nature of the initial fibrous layer and the nonwovenfabric to be produced, the energy flux exerted by the liquid streams maybe adjusted as desired by varying the size of the orifices from whichthe streams emerge, the pressure at which the liquid is delivered, thedistance the web is separated from the orifices, and the type oforifice. Other process variables, which may be manipulated in order toachieve the desired nonwoven fabric include the speed of the fibroussheet, the number of times it is passed into the path of the streams,and/ or the directions in which it is passed into the path of thestreams.

Wherever the columnar streams act on the sheet, individual fibers in thesheet are forced into an interentangled relationship with each other inall dimensions of the sheet. A single stream, or a multiplicity ofstreams spaced a preselected distance apart, depending on the effectdesired, may be applied continuously or intermittently to the sheetmaterial in a direction perpendicular or oblique to its surface. Thefibrous sheet material may be treated along its lengthwise directionand/or transversely and/or obliquely thereto. The fibrous sheet materialmay be treated from one side only or from both sides, the latter beingcarried out in successive steps.

The individual streams must be of sufficient fineness to produce thedesired filament interentanglement Without permanently separating groupsof fibers, i.e., without forming openings in the sheet. In general, thestreams are formed by orifices of 2 to 15 mils in diameter (preferablyless than 10 mils). Orifice size may also be varied depending on thematerial to be treated and the effect desired. In general, for treatingloose fibrous batts and the like is is preferred to vary the orificesize according to the basis weight of the sheet and the denier of thefibers therein. Preferably small diameter orifices are used for lowbasis weight, low denier materials, While larger orifices are used asthe weight or denier increases.

During treatment, the fibrous web can be supported by a screen or otherapertured support or a solid surface such as a fiat plate or a bar. 'Ifa screen or similar apertured support is used, it is preferably selectedin accordance with conditions illustrated in the examples. As shown inthe examples, jet-track-patterned nonwoven fabrics and substantiallynonpatterned nonwoven fabrics can be prepared on a variety of screens byadjusting these variables or by treating the Web While supported againsta solid plate or bar.

EXAMPLE 1 This example illustrates the treatment of different initialmaterials with streams of water issuing from 0.015 inch orifices toprepare nonwoven fabrics having seams arranged in a crisscross pattern.

A 2.5 oz./yd. web of randomly disposed fibers is prepared by a randomweb air-laying technique from 3.7 denier per fiber (d.p.f.), Australiantops wool. By assembling layers of this web, a series of initialmaterials of 5, 10 and 20 oz./yd. is prepared. A similar series ofinitial materials is prepared from a blend of 50% by weight of 1.5denier per fiber (d.p.f.), 1.5 inch long, acrylic fibers and 50% byweight of 1.5 denier per fiber, 0.25 inch long rayon fibers.

Using apparatus of the type shown in FIGURE 4, each initial material istreated with essentially columnar streams of water issuing from orificesdrilled in line in a manifold at a spacing of 5 orifices per inch.Special care is taken in the cleaning and boring of the orifices to getas sharp an entry into the orifice as possible to minimize any breakingup of the stream issuing from the orifice. Uniformity of waterdistribution to the orifices is facilitated by use of a cylindircalfilter which is mounted coaxially within the manifold assembly, spacedfrom the walls thereof, and extends over the full length of theassemlby. The filter is a fine mesh wire screen x 80 wires per inch and36% open area).

The initial material is placed on a support screen and is passed underthe streams of water so that they traverse one major direction of theinitial material, which is then removed from the screen, turned over,replaced on the support screen and treated in the direction transverseto the first treatment. Sufiicient passes under the streams are used toprovide for treating each initial material with an energy ofapproximately 2 HP-hr./lb. of initial material, the passes being equallydivided between the two directions of treatment. During passage underthe streams, the initial material is moved at about 2 yds./min. and isspaced about 1 inch from the orifices. The support screen is either a 20mesh (20 x 20 wires/ inch, 29% open area) or an 80 mesh (80 x 80 wires/inch, 30% open area) woven wire screen. Treatment conditions for eachinitial material are summarized in Table I.

The products obtained have criss-cross seam-like lines of fiberentanglement corresponding to the lines of passage of the liquid streamsand spaced accordingly (i.e., 5 seams/inch). They are strong andfabric-like in aestetics. When tested in the absence of any addedbonding agent or further bonding method, the products have anentanglement completeness E greater than 0.5 and Table I ProcessingConditions the final pattern of the nonwoven fabric because the jetstreams are advanced repeatedly along the same paths to give a producthaving the same number of lines as there are orifices per inch.Treatment involves (l) passing Product Properties Inrtlal MaterialEnergy u tensile Entamzle, Entalmle.

Support Orifice of streams Total Energy Water strength l Sample Weightscreen size (ft.-poundals/ No. of expended pressure (lb./1n.// frequency(I) Comp 9 code Composition (on/yd? (mesh) (inch) in. see.) passes(HP-hr./lh.) (p.s.i.g.) z./yd. (No./1n.) ness (0) A Acrylic/rayon 20 0.015 1, 100, 000 64 2 200 1. 3 23 0. 53 B d 5 80 0. 015 1, 100, 000 67 2200 l. 7 l0 0. 45 5 80 0. 015 4, 400, 000 18 2 500 3. 0 3) 0. 62 20 0.015 l, 100, 000 128 2 200 l. 3 22 0. 54 5 80 0. 015 1, 100, 000 67 2200 1. 9 21 0. 88 10 2O 0. 015 1, 100, 000 128 2 200 1. 5 10 0. 79 20 200. 015 1, 100, 000 256 2 200 1. 1 20 (l 88 EXAMPLE 2 the supported webunder the streams of Water so that This example illustrates thesynergistic effect obtained when using small orifices, closely spacedand using Water pressures greater than 200 p.s.i. g.

A series of samples, coded A through N, is prepared using as initialmaterial a 2.5 oz./yd. web of randomly disposed fibers prepared by arandom web air-laying technique. Each web is prepared from a 50/50blend, by Weight, of 1.5 inch long, 1.5 denier per filament acrylicfibers and 0.25 inch long, 1.5 denier per filament rayon fibers. Foreach sample, the web is supported on a screen and treated by passing itback and forth under essentially columnar streams of water issuing fromorifices drilled in line in a manifold to thereby produce in the web aseries of lines of fiber entanglement corresponding they traverse onemajor direction of the material for a given number of passes, providingone-half of the total energy expended in the treatment, each passfollowing the same path so that the streams strike the web in the sameplace during each pass, and (2) turning the web over, replacing it onthe screen, and repeating the first treatment in a direction 90 thereto.Sufiicient total passes under the streams are used to provide for totaltreatment of the web with an energy of approximately 2 HP-hr./lb. ofweb. During treatment, the web and screen support are moved on aconveyor belt at a speed of 2 yds./min. and the web is spaced about oneinch from the orifices. Treatment conditions are summarized in Table II.

TABLE II Srip tensile Total Energy Energy flux Support strength Or ficeOrifices Pressure passes (HP-hr. (ft.-poundals screen (lb. /in per size(m.) per meh (p.s.i.g.) o.) llb.) per infi-see.) (mesh) oz. /yd.

0. 007 20 500 8 2 4. 4X10 80 3. 92 0. 007 20 500 8 2 4. 4X10 80 3. 38 0.007 20 500 8 2 4. 4X10 2O 2. 88 0. 007 20 200 32 2 1. 1X10 80 2. 95 0.007 20 200 32 2 1. 1X10 20 2. 47 0. 007 20 200 32 2 1. 1X10 80 1. 95 0.030 5 200 8 2 1. 1X10 20 1. 10 0. 030 5 200 8 2 1. 1x10 80 0. 007 20 10064 2 0. 4X10 20 0. 85 0. 007 20 100 64 2 0. 4X10 80 0. 030 5 100 16 2 0.4X10 2O 0. 79 0. 007 5 100 128 2 0.4)(10 20 0. 16 0.030 5 500 2 2 4.4X10" 20 O. 030 5 500 2 2 4. 4X10 8O 1 Line-patterned product notachieved since particular screen/orifice size/pressure/web combinationsled to bubbling, washing away, or blowing apart of the we in number tothe number of orifices in the manifold.

The orifices are carefully cleaned and bored to get as sharp an entryinto the orifice as possible to minimize any breaking up of the streamissuing from the orifice. When using the manifolds having orificesspaced S/inch, uniformity of water distribution to the orifices isfacilitated by use of a cylindrical filter which is mounted coaxiallywithin the manifold assembly, spaced from the walls thereof, and extendsover the full length of the assembly. The filter is a fine-mesh wirescreen (80 x 80 wires per inch and 36% open area). A manifold of thetype shown in FIGURE 9 is used when the orifices are spaced 20/inch.Either arrangement is satisfactory regardless of orifice size andspacing. During treatment the web is placed on a waven wire supportscreen of either 20 mesh (20 x 20 wires per inch, 29% open area) or 80mesh (80 x 80 wires/inch, 36% open area), which screen serves to supportthe web and does not influence EXAMPLE 3 (A) In operating the process ofthis invention, velocity and consequently momentum of the discretecolumn of fluid contacting the fibers must be sufficiently high as tophysically drive the fibers into an interentangled relationship withother fibers. The actual velocity required is dependent on the nature ofthe fibrous sheet to be treated and on the degree of fiberinterentanglement desired. Velocity may be adjusted to any desiredlevel, for example, by varying the pressure on the liquid in FIGURE 1.In Table III, the eflect of varying the pressure and/ or the orificesize is shown. In each case, the starting material is a continuousfilament web. The Web is placed on a 30- mesh screen and treated usingapparatus of the type shown in FIGURE 4. The web is subjected to twopasses, one transverse to the other, on each side of the web and ispassed so as to just contact the orifices.

TABLE III Strip tensile Orifice strength Modulus Drape Orifice spacingPressure (lbs./in./ Elongation lbS-Illl flex (111.) (N0./1I1.)(p.s.i.g.) oz./yd. (percent) oz./yd (cm.)

of untreated Web for comparison- 0. 14 53 0. 07 1. 6

(B) Additional samples are prepared using another 20 or 40 lines ofentanglement per inch. These entangled initial Web. The web is composedof randomly disposed, 15 regions are present at sufiicient frequency toprovide crimped, continuous, bicomponent filaments composed of strengthand coherency to the nonwoven fabric as may be equal weights ofpolyhexamethylene adipamide and a seen from the tensile strength,ranging from 2,9 to 6.1 copolyamide of hexamethylene adipamide andhexalbs/in. per oz./yd. and entanglement completeness values methylenesebacamide units (80/20). Filament denier is 5 ranging from 0.94 to 1.3.Entanglement frequency 2.6 and filament tenacity is 2.1 grams perdenier. Specific processing conditions are given in Table IV. For eachsample, a web is placed on a woven wire screen, which serves merely tosupport the web during treatment. The supported web is passed underessentially columnar values T from 20 to 217, indicating adequate toexcellent surface stability. The products of this invention as shown inTable IV were all prepared at energy flux values greater than 12 10ft.-poundals/in. sec. and energy values greater than 0.12 HP-hr./ lb. offabric.

TABLE IV Enten- Test Energy gle- Entandirec- Strip 5% Orifice Belt (Icom ment Web tion tensile secant diam- Orifice Water speed Supportpoundals Energy plete- Freweight (MD strength Elonmodulus eter spacingpressure (yds. screen per in. (Hp-hr./ 1125 5 quenc (02.! p or(lb.1in.)/ gation (lb./in Sample (in.) (No./in.) (p.s.i.g.) lmm.) (mesh)5 sec.) lb.) (0) (t) yd!) XD) (om/yd!) percent (ozJydfi) A 0.0025 402,000 20 x10" 0. 12 1. 2 29 3. 61 MD 5. 86 201. 6 1. 12 X1) 5. 20 213.0 1. 27 B 0.0025 2, 000 10 30 35 10= 0. 29 1.2 20 2. 96 MD 5. 23 179. 50. 97 XD 4. 34 217. 5 0. 79 40 2, 000 5 30 35X10 0. 65 1. 0 34 2. 63 MD5. 34 169 1. 4'8 XD 4. 64 182 1. 43 40 2, 000 20 30 35x10 0. 51 1 2 403.33 MD 5. 98 206. 6 1. KB 4. 13 190. 7 1. 64 20 2, 000 21 30 35X10 0.35 4. 66 MD 4. 48 20 2,000 10. 6 30 35X10 0.61 4. 50 MD 5. 38 20 2, 0005. 35 30 35X 10 1. 04 5. 94 MD 3. 96 20 2, 000 40 30 35 10 0. 22 3. 83MD 2. 91 20 2,000 21 30 35X10 0. 16 5. 0 MD 4. 2 20 2, 000 11 30 35x100. 51 6. 1 MD 5. 5 20 2,000 5. 5 30 35X10 1. 02 6. 1 MD 5. 5 20 2, 00020 80 35 l0 0. 39 4. 41 MD 5. 69 XD 4. 73 20 2, 000 10 30 35X10 0. 86 3.93 MD 6. 07 XD 4. 28 20 1, 000 20 30 l2 l0 0. 14 4. 14 MD 4. 58

streams of water from sharp-edged orifices arranged 1n EXAMPLE 4 line ina manifold at the given spacing per inch. The orifices are carefullycleaned and bored to get as sharp an entry into the orifice as possibleto minimize any breaking up of the stream issuing from the orifice.Uniformity of water distribution to the orifices is facilitated by useof a manifold of the tape shown in FIGURE 9. Unless otherwise indicated,each web is passed under the streams two times, one pass at right anglesto the other, and is then turned over on the screen and again given 2passes, one at right angles to the other, for a total of 4 passes.During treatment the web is spaced about 1 inch from the orifices, andis moved under the orifices on a conveyor belt, at the speeds indicatedin Table IV.

All of the products are characterized by the presence of lines ofentanglement when viewed from at least one surface of the product,corresponding in number to the number of orifices per inch in thetreatment manifold, i.e.,

(A) In operating the process of this invention, the fibrous sheetmaterial is preferably treated while in contact with or fairly closetothe orifice. As the distance from the orifice increases passage of theliquid through the air causes turbulence and/or a breaking up of thecolumnar flow which reduces the extent or intensity of fiberinterentanglement obtainable. This is illustrated in the table belowwith respect to treatment of a continuous filament web, usingdrilled-tube orifices of the type discussed prior to the examples inconnection with the table of energy flux values, and a water pressure of2000 p.s.i.g. Using tenacity as an indication of the extent of fiberinterentanglement, it is observed from the table that the extent offiber interentanglement generally decreases as the distance from theorifice increases. All other factors being equal, the extent of fiberinterentanglement decreases as the pressure decreases.

(B) In a similar experiment, a series of samples is prepared using a webof continuous, polyethylene terephthalate filaments having a filamentdenier of 1.3 and a filament tenacity of 3.6 grams per denier.Processing conditions are as in Example 3B unless otherwise indicated inTable V. Products A, B and D through I are characterized by the presenceof lines of entanglement corresponding in number to the number oforifices per inch in the treatment manifold, i.e., 20 or 40 lines ofentanglement per inch. Products given 1 pass have entanglement lines inone direction only. Those given passes at 90 to one another have linesof entanglement in 2 major directions of the fabric. The presence oflines of entanglement at these frequencies, i.e., 20 or 40/inch,provides good strength and coherence as may be seen from the followingsummary of the properties of the nonwovens:

Tensile strength-6 to 8.5 (lb./in.)/(oz./yd. Entanglement completeness50.85 to 1.0 Entanglement frequency T-16 to 39 Energy (HP-hr./lb.)0.31to.1.47

Energy fiux (ft.-poundals/in. sec.)-4.4 to 35x10 From a comparison ofSamples A and B with Sample C and of Samples H and I with Samples I andK, it may be seen that for a given set of conditions, including theparticular manifold, initial web, etc., treatment efficiency decreasesas the web-to-orifice spacing increases. Thus for the particularconditions of these samples, spacing of 5.6 inches was enough to breakup the stream and make it sufiiciently turbulent to prevent entanglementof the web in lines corresponding to the number of orifices.

Orifice size may also be varied depending on the material to be treatedand the effect desired. In general, for treating loose fibrous batts andthe like, it is preferred to vary the orifice according to the basisweight of the sheet and the denier of the fibers therein. Preferably,small diameter orifices (e.g., 0.0028 inch) are used for low basisweight, low denier materials, While larger orifices (e. g., 0.005 inchor 0.007 inch) are used as the basis weight or denier increases.

(B) Additional samples are prepared, using as initial material 'webs ofthe type described in Example 4B. In treating the webs, the number ofpasses is varied from 1 to 8. However, all repeat passes involve movingthe web under the streams along the same path as the first pass so thatthe streams strike the web in the same place during each pass. Otherprocessing conditions are as in Example 2 unless otherwise specified inTable VI.

The products obtained, as viewed from one fabric face, have 40 lines ofentanglement per inch in one major direction of the fabric. Thisprovides good strength and stability in both directions of the fabric asmay be seen TABLE V Energy Entan- Entan- Strip Strip nx glegletensiletensile Orifice Orifice Web, Belt (it. ment ment Web strength strengthdiamspacln orifice Water speed Support ponndals Energy Com- Freweight(MD) (XD) b eter (N 0.]in. spacing pressure No. of (ydsJ screen per in.B (HP-hrs] pletequeney (oz.l (lb./in.)/ (lb./in.)/ Sample (111.)(No./in.) (in.) (p.s.l.g.) passes min.) (mesh) see.) lb.) ness (0) (f)yd. (oz./yd. (oz./yd.

A 0. 0025 40 1 2. 83 80 x10 0. 31 1. 0 16 2. 67 7. 68 7. 02 B 0. 0025 1("7 0. 71 80 35X10 1. 47 0.85 17 2. 38 5. 99 6. 77 0. 0025 40 5. 6 0.7130 35x10 2. 28 2.8 0. 005 20 1 2, 000 4 12. 5 30 35X 10 0. 94 1. 0 36 3.04 7. 71 7. 51 0. 005 20 1 500 s 4 1. 4 30 4. 4X10 1. 00 0. 88 17 3. 006. 41 8. 05 0. 007 20 1 1, 000 B 4 7. 5 80 12X1 0 0. 52 0. 05 29 3. 057.01 8. 17 0. 007 20 1 500 B 4 2. 30 4. 4X10 0. 64 0. 90 20 2. 54 7. 057. 36 0. 007 20 1 11. 4 35x10 0. 31 0. 24 2. 71 7. 76 6. 32 0. 007 20 12. 86 80 35x10" 1. 17 0. 94 39 2. 87 8. 39 8. 46 0. 007 20 5. 6 11. 4 8035x10 0. 42 2. 10 2. 73 0. 19 0. 007 20 1 2. 86 80 35X 10 1. 35 2. 5

l 80 mesh=80X80 wires/in, 30% open area. 30 mesh=30 30 wires/id, 40%open area.

-MD tested in direction of lines or entanglement. XD tested 90 to MD.

c Complete treatment includes: 1 pass, 500 p.s.i.g.. using 16 x 18 mesh,71% open area top screen. Sample turned over, 1 pass, 2,000 p.s.i.g., notop screen.

EXAMPLE 5 Complete treatment includes: 1 pass, 500 p.s.i.g., using 16 x18 mesh, 71% open area top screen. Sample turned over, 1 pass, 2,000p.s.i.g., using some top screen; 1 pass, 2,000 p.s.i g., no top screen.

2 passes, 1 at 90 to other; sample turned over; 2 passes, 1 at 90 to oier.

l Sample nonuniform; properties could not be determined.

from the properties in Table VI, wherein the following ranges are seen:

Strip tensile strength-4.5 to 7.3 (lb./ in.) (oz./ yd?) Entanglementcompleteness E0.82 to 0.92 Entanglement frequency T10 to 18 Energy-0.15to 1.16 HP-hr./lb.

Energy fiux23 10 ft.-poundals/in. sec.

In general, for these webs, an energy of 0.15 is adequate to provide astrong, well-entangled product. Increasing the energy to 0.26 or more,all other conditions remaining unchanged improves the surface stabilityof the nonwoven fabric as shown by the increased entanglement frequencyvalues obtained in Samples B, C and D.

50% by weight of 0.25 inch, 1.5 d.p.f. rayon fibers. The web is placedon a fiat metal plate and is passed under TABLE VI Energy Strip flux(tt.- Entangle- Entangle- Web Test tensile 5% secant poundals Energy Fment weight direction strength modulus No. of per mi (HP-hrJ comp 2requen; (z./ (MD or (1b./in)/ Elongation (lb./in.)/ Sample passes sec.)lb.) ness (0) ey (f) yd!) XD) (oz./yd. (percent) (oz./yd.

A 1 2s 10 0.15 0.87 10 2. 41 3 B 2 523x10 0.26 0.84 18 811 22 c 4 23x100. 61 0.82 17 2. 46 3 i D s 23 1o 1.16 0.92 17 3 3i? B MD is tested indirection of lines of entanglement; XD is tested 90 to MD.

NOTE.-Processing conditions common to all samples:

Orifice diameter: 0.0025 inch. Orifices per inch: 40. Web-orificespacing: 1 inch. Water pressure: 1,500 p.s.i.g. Belt speed: 3.64 yardsper minute. Support screen: 30 x 30 wires/inch, 40% open area.

EXAMPLE 6 This example illustrates preparation of a nonwoven fabrichaving 20 lines of entanglement per inch, using a flat bar to supportthe web during treatment.

The initial material is a web of randomly disposed fibers prepared by arandom web air-laying technique. The web contains 50% by weight of 1.5inch, 1.5 denier acrylic fibers and 50% of 0.25 inch, 1.5 denier acrylicfibers, and weighs about 3 0z./y-d. The web is treated with essentiallycolumnar streams of water issuing from 0.007 inch diameter orifices,drilled in a line in a manitold at a frequency of 20 orifices/inch. Theweb is held against the fiat surface of a one-inch wide metal bar, whichis held stationary during treatment. The web is spaced one inch from theorifices during treatment and is moved over the bar at a speed of 2yards per minute. The streams of water strike the web and then the flatsurface of the bar at about 90 to the fiat surface. The web is passedunder the streams once using a water pressure of 500 p.s.i.g. and onceusing 1,000 p.s.i.g. It is then turned over and passed once more underthe streams, at 1,000 p.s.i.g. while held against the flat bar. Energyflux of the streams at 1,000 p.s.i.g. is 12. ft. poundals/in. sec. andtotal energy expended in the treatment is 1.4 HP.-hr./ lb. All passesare done in one major direction of the web and the resulting nonwovenfabric has lines of entanglement per inch in one fabric direction,corresponding to the number of orifices per inch. This provides goodstrength and stability as can be seen from the following properties:

Strip tensile strength (lb./in.)/(oz./yd. )--MD, 4.6;

Elongation (percent)--MD, 65; XD, 76

5% secant modulus (lb./in.)/(oz./yd. )MD, 0.4;

Entanglement completeness c--0.98

Entanglement frequency f22 Surface stability-top face, 3.8; bottom face,4.5

Note:

M Dtested in direction of lines of entanglement XD-tested 90 to MDSurface stability-top face, 3.8; bottom face, 4.5 end of thespecification EXAMPLE 7 This example illustrates preparation of anonpatterned nonwoven fabric using a flat, solid support plate for theweb.

The initial material is a 2.9 oz./yd. web of randomly disposed staplefibers, prepared by a random web airlaying technique and consists of 50%by weight of 1.5 inch, 1.5 denier per filament (d.p.f.), acrylic fibersand essentially columnar streams of water issuing from 0.007 inchdiameter orifices drilled in a single line, 21 inches long, on 0.05 inchcenters (20/inch). During treatment, the plate is positioned so that thestreams are directed against it at about 90 to its fiat'surface. Watertemperature during treatment is about C. The orifice manifold isoscillated at approximately 300 oscillations per minute; diameter ofoscillation path is 0.5 inch. The web, supported on the plate, is passedunder the streams at a speed of 2 yd./min. and spaced approximately 0.5inch from the orifices. A coarse mesh screen is placed over the webduring the entire treatment to restrain the web. Processing is asfollows:

1 pass using 500 p.s.i.g. pressure, 2 passes using 1,000 p.s.i.g.pressure, sample turned over on the plate, and 2 passes using 1,000p.s.i.g. pressure. All passes are done in one major direction of theweb. Energy flux of'the streams is 12 x10 ft.-poundals/inch sec. andtotal energy expended is 2.2 HP.-hr./lb. Properties of the final fabricare as follows:

Weight (oz./yd. )2.3

Str3ip4tensile strength (lb./in.)/ (oz./yd. )-MD 4.2; XD, Elongation(percent)-MD, 61;XD, 82

Entanglement completeness 5-0.7

Entanglement frequency T-43 Surface stability (both faces) 3.8

Note:

MDtested in one major direction XDtested 90 to MD Surface stability isdetermined as described near the end of the specification.

As can be seen from the foregoing discussion and the examples, theprocess of this invention offers a high speed economical route to theproduction of a wide variety of textile products. In order to obtain thehigh degree of fiber interentanglement which characterizes the productsof this invention, the starting material is acted upon by disiclretecolumnar streams of liquid moving at high energy The fluid must be aliquid, since the stream must be capable of maintaining its identity asa discrete column for a finite distance beyond its point of emergencefrom the orifice. Compressible fluids, such as air, nitrogen, or othergases, which diffuse rapidly upon emerging from a nozzle orifice, arenot effective. The results obtained by treatment with water and nitrogenare compared in the following example.

EXAMPLE 8 A loose web consisting of randomly disposed continuousfilaments is used as the starting material. Using 23 apparatus of thetype shown in FIGURE 4, a sample of the web is placed on a 30-meshscreen and passed in contact with 0.0028 inch orifices on 0.025 inchcenters (40 orifices/inch) supplied with water at 2,000 p.s.i.g. pres- 1Strip tensile strength Modulus Drape (lbs./in.)/ Elongation (lbs./in.)/flex Treatments (SidOS)! (oz./yd. (percent) (oz. yd!) (0.111)

Untreated web 0.14 53 0.07 1. 6 0.0028 inch orifice 3. 42 156 1.00 2.20.007 inch orifice 3. 68 168 0. 93 2. 2

The marked increase in tensilestrength of the water- 'treated samplesshows that a high degree of fiber interentanglement has occurred.

The above two experiments are then repeated on additional samples of theweb under identical conditions except that nitrogen at 2,000 p.s.i.g.pressure is used instead of water. The nitrogen-treated samples areremoved and examined. A few surface fibers appear to have been blownaround but no other visible effect is noted. The strength of thesesamples is substantially unchanged from that of the untreated web.

The above experiments are then repeated using a staple fiber batt as thestarting material. Again, treatment with the high velocity liquidstreams is observed to interentangle the fibers whereas treatment withthe gaseous streams has no effect.

In a final test in this series, a sample of the staple batt is firstmoistened with water and then subjected to the action of nitrogen from0.007 inch orifices at 2,000 p.s.i.g. pressure. No fiberinterentanglement is observed.

EXAMPLE 9 This example illustrates the synergistic effect obtained byusing small orifices, close spacing, and water pressures greater than200 p.s.i.g., for making substantially non-patterned products.

(A) A series of samples coded A through Q, is prepared, using as initialmaterial a 2.5 oz./yd. web of randomly-disposed fibers prepared by anair-laying technique. Each web is prepared from a 50/50 blend, byweight, 1.5 inch long, 1.5 denier per fiber acrylic fibers and 0.25 inchlong, 1.5 denier per fiber rayon fibers. For preparation of each sample,the web is supported on a screen (80 X 80 wires/inch, 31% open area) andpassed under the jet streams at 2 yards/minute. The total passes underthe jet streams are listed in Table VII; half the passes are done withthe streams contacting one side of the web, after which the web isturned over on the screen and treated with the remaining number ofpasses under the streams. The streams are essentially columnar streamsof 50 C. temperature water issuing from orifices drilled in line in amanifold which is oscillated at 300 r.p.m.; the orifices being about oneinch from the web during treatment. The orifices are carefully cleanedand bored to get as sharp an entry into the orifice as possible tominimize any breaking up of the streams issuing from the orifice. Whenusing manifolds having orifices spaced per inch, uniform waterdistribution to the orifices is facilitated by use of a cylindricalfilter which is mounted coaxially within the manifold assembly, spacedfrom the walls thereof, and extends over the full length of theassembly. The filter is a fine-mesh wire screen (80 x 80 wires/inch and36/ open area). A manifold of the type Cit shown in FIGURE 9 is usedwhen the orifices are spaced 20 per inch. Either arrangement issatisfactory regardless of orifice size and spacing. During treatment,sufficient total passes under the streams are used to provide for totaltreatment of the web with an energy of the order of 2 HP.-hr./lb. ofwave. Actual treatment energies are given in Table VII. Duringtreatment, vacuum is employed under the support screen (13 inches ofwater). The support screen does not influence the final pattern of thenonwoven fabric because of its fine mesh in relation to the otherconditions employed; a slight surface pattern corresponding to theoscillation pattern of the jets is seen in the final product; however,the product is smooth, dense and when viewed by transmitted light showsa substantially uniform distribution of fibers area-wise. The treatmentreorients fiber segments transversely with respect to the plane of theweb, i.e., in the thickness direction of the web; these transverselydisposed fiber segments are substantially randomly distributedthroughout the area of the fabric.

Samples A through G of Table VII show what happens when pressure isvaried for the indicated orifice size (0.030 inch diameter orifice) andspacing (5 orifices per inch). Thus, for this orifice and spacing, apressure of p.s.i.g. yields products with tensile strength of about 0.7(lb./in.)/oz./yd. Strength increases to about 1.5 (lbs./in.)/(oz./yd. at200 p.s.i.g.; treatment at 1,000 p.s.i.g. destroys the sample. Allsamples prepared with these large jets and this spacing have neither asmooth texture nor a nonpattcrned appearance.

From Samples H through L, the effect of reducing orifice size, whilekeeping the same orifice spacing, can be seen. At 100 and 200 p.s.i.g.,the smaller diameter orifice (0.007 inch) gives weaker products than didthe 0.030 inch diameter orifice. Unexpectedly, however, at 500 p.s.i.g.,strengthens obtained with the 0.007 inch diameter orifice are higherthan with the 0.030 inch diameter orifices. In addition, the productsmade with the 0.007 inch diameter orifice at a spacing of 5 per inch aresatisfactory in terms of aesthetic properties, i.e., appearance andtexture.

The effect of both reducing the orifice size to 0.007 inch andincreasing the orifice frequency from 5 per inch to 20 per inch can beseen from Samples M through Q of Table VII. At 100 and 200 p.s.i.g. theincreased frequency does not yield greater tensile strength; however, ascan be seen from Samples P and Q, the most desirable products from thestandpoint of high strength and satisfactory appearance are achievedwhen all three conditions (small diameter orifices, close spacing, andhigh pressure) are employed; thus, at 500 p.s.i.g., with the 0.007 inchorifices spaced 20 per inch, a strength of 3.48 is achieved. This isfurther increased by going to 1,000 p.s.i.g., as shown by Sample Q,where a tensile strength of 4.3 (lbs./in.)(/oz./yd. is reached.

(B) In Table VIII, data for a similar set of products prepared usingrayon fibers are shown. In Example 9B, all process conditions are asshown in the table or as described for Example 9A with the exceptionthat the starting web is 100% rayon and has a nominal weight of 2oz./yd. for Samples A through M and 6 oz./yd. for Samples N through V.For 2 oz./yd. webs of rayon, it is seen from Table VIII that a tensilestrength of about 2 (lbs./in.)/(oz./yd. can be achieved at 200 p.s.i.g.,when using the 0.007 inch diameter orifices spaced either 5 per inch or20 per inch.

From Samples A to D of Table VIII, the effect of varying pressure whenusing 0.030 inch diameter orifices, spaced 5 per inch, is shown. Noproducts having satisfactory appearance and texture are obtained. Atensile strength of 0.86 is obtained at 100 p.s.i.g., and of 1.48 at 200p.s.i.g.; increasing the pressure to 500 and 1,000 p.s.i.g. results indestruction of the sample.

Samples E through G, when compared to A through D, show the effect ofdecreasing orifice size from 0.030 to 0.007 inch in diameter, withspacing remaining at 5 per inch and the pressure being varied. All ofthe products E through G are satisfactory from the appearancestandpoint. The sample prepared with 0.007 inch diameter orifices at 100p.s.i.g. is weaker than that prepared with 0.030 inch orifices at 100p.s.i.g. However, at 200 p.s.i.g. the

26 EXAMPLE 10 This example illustrates preparation of a substantiallynonpatterned product by interrupting the essentially columnar streamsbefore they strike the web.

reverse is true; increasing to 500 p.s.i.g. still further in- T einitial Web is a Web of randomly disposed fibers decreases the strengthto 3.37 (lbs./in.)/(oz./yd. when p f y an y g technique (Rando-Webber).The 0.007 inch orifices are used, whereas 500 p.s.i.g. destroys web 1sprepared from a 50/50 blend, by weight, of 1.5 the web when 0.030 inchorifices are used. inch, 1.5 d.p.f. (denier per fiber) acrylic fibersand 0.25 Samples H through M, when compared to B through Inch, 1.5d.p.f. rayon fibers. During treatment, the web is G, illustrate theeffect of increasing the orifice frequency supported on an 80 x 80wires/inch, 31% open area from 5 to 20 orifices per inch. From Sample Hvs. Samscreen; an 18 X 14 Wires/inch. 5% p n area top screen ple B, itis seen that merely increasing the frequency, for is placed on the webto help hold it in place during treatthe 0.007 inch diameter orifice, at100 p.s.i.g., does not ment; neither screen serves as a patterningdevice. The result in an increased strength. However, when small di- 15assembly is moved under the streams at 2 yards per minameter orifices,close spacing, and 200 to 1,000 p.s.i.g. ute, spaced about one inchbeneath the orifices. The manipressure are used (Samples I to M), themost desirable fold used is of the type shown in FIGURE 9. It has 21products (strength and aesthetics) are obtained. single line of 0.005inch diameter orifices, spaced 40' per With the 6 oz./yd. Webs, the0.030 inch diameter oriinch. Essentially columnar streams of 60-70" C.water fices, spaced 5 per inch (Samples N-Q), do not yield issue fromthe orifices. The orifices are carefully cleaned satisfactory productsat 100 to 500 p.s.i.g.; 1,000 p.s.1.g. and bored to get as sharp anentry into the orifices as posdestroys the web. 811216 to minimize anybreaking up of the streams issuing In contrast, when 0.007 inch diameterorifices, spaced from the orifices. However, before the streams contact20 per inch are used (Samples R-V), strong products (3-4 the web theyare interrupted by oscillating (approximate lbs/in. per oz./yd. withdesirable appearance can be 25 frequency is 3 cycles per second) ascreen in the path of obtained at 500 to 1,000 p.s.i.g. the streams.This screen is spaced about midway between TABLE v11 Strip tensilestrength Orifice Total Ene y Energy flux Product (lb./in. Product sizeOrifices Pressure passes (HP-hr./ (ft.-pounda1s weight per 02.] appear-(in.) per inch (p.s.i.g.) (no.) lb.) per mi -sec.) (om/yd!) yd.) ance0.030 5 100 16 1.0 386,000 2.0 0.66 NS 0.030 5 100 16 1.8 386,000 2.130. 74 NS 0.030 5 200 8 2.1 1,000,000 2.3 1.4 NS 0.030 5 200 8 2.1 ,090,0 2.36 1.6 NS 0.030 5 500 2 1.8 4,310,000 2.2 2.2 NS 0.030 5 500 4 2.24,310,000 3.65 2.32 NS 0030 5 1, 000 2 4.4 12,200,000 NS 0. 007 5 100256 1.4 386.000 2.21 0.04 s 0. 007 5 100 144 0.8 386,000 2.10 0.02 s 0.007 5 200 128 1.8 1,090,000 2.37 1.02 s 0. 007 5 500 64 3.7 4,310,0002.27 2.92 s 0. 007 5 500 64 3.6 4,310,000 2.35 3.18 s 0. 007 20 100 701.4 6, 000 2.35 0.06 s 0. 007 20 200 40 2.3 1,090,000 2. 28 0.23 s 0.007 20 200 40 2.1 1,090, 000 2.55 0.22 s 0. 007 20 500 10 2.3 4,310,0002.25 3. 48 s 0. 007 20 1, 000 4 2.6 12,200,000 2.31 4.31 s

* Average of MD and XD. Sample destroyed by streams.

NS Not satisfactory for uses requiring smooth, dense nonpatternedappearance; all NS products have irregular, blotched appearance andlumpy texture.

S Satisfactory for uses requiring smooth, dense, nonpatterendappearance.

TABLE VIII Strip tensile strength Orifice Orifices Total Energy Energyflux Product (lb./in. Product size per Pressure passe (HP-1m](ft.-poundals wel ht per 02.] appear- (in.) inch (p.s.i.g.) (no.) lb.)per misec.) (ea/yd yd.)* ance de: fii f? 0. 030 5 100 16 2. 1 386, 000 170 0. 86 NS 5 200 8 2.0 1, 090,000 2. 48 48 NS 5 500 4 4.0 4,310,000 NS5 1, 000 2 5 5 12, 200,000 NS 5 100 256 1. 5 386, 000 2. 02 0. S 5 200128 2. 1 1, 090, 000 2. 06 2. 14 S 5 500 64 4. 2 4, 310, 000 2. 03 3. 37S 20 100 70 1. 7 386,000 1. 98 0. 11 S 20 200 20 1. 3 1, 090, 000 2. 032. 07 S 20 200 40 2. 5 1, 090, 000 2. 09 1. 69 S 20 500 8 2.1 4,310,000 1. 97 3. 58 S 20 1, 000 2 1. 5 12, 200, 000 2. 07 3. 66 S 20 1,000 4 3. 0 12, 200, 000 2. 13 3. 47 S 5 100 32 1. 4 386, 000 5. 53 1. 68NS 5 200 16 1. 7 1, 090,000 5.97 1. 99 NS 5 500 8 2.0 4, 310,000 7.94 1. 72 NS 5 1, 000 4 3. 7 12, 200, 000 NS 20 100 250 2.0 386,000 S 20200 100 2. 2 1, 090, 000 6. 13 0. 33 S 20 500 22 1. 9 4, 310, 000 6. 033. 66 S 20 1, 000 4 1. 0 12, 200, 000 6. 70 4. 39 S 20 1, 000 8 1. 9 12,200, 000 6. 4. 23 S Average of MD and XD. Sample destroyed by streams.Too weak to test.

NS Not satisfactory for uses requiring smooth, dense, nonpatternedappearance; all NS products have irregular blotched appearance and lumpytexture.

